Sadly, there are a certain percentage of people who are pathological liars, meaning that they lie without even thinking about it as being a lie. In fact, they may even believe the reality that they construct.
Then there are the manipulative liars, fully aware of what they are about and being strategic about making others look bad and themselves appear better in comparison. These people will lie about the work they themselves do, and they will lie to you and about you to other people.
Once you've figured out that you are dealing with either type of liar, you must take steps to protect yourself and your reputation in the organization. Here are some techniques that you can use:
1)Very quickly avoid trying to resolve issues with them as you would with a person of integrity. All that does is put you in a situation of vulnerability. They will just use the information you share with them and will see your efforts to resolve issues with them as an indication of weakness.
2)Calmy and directly confront the liar immediately upon the lie-whether it occurs in front of witnesses or not. Simply state the truth and then avoid the crazy arguing that the liar will try to engage you in. If that person is a liar, it's not just you in the organization that will know it, and your standing up to him or her might give someone else the courage to do so as well. A liar is a bully, and bullies need standing up to or they run amok.
3)NEVER meet alone with a liar to resolve a situation as you would a regular colleague. Doing so will set you up for further lies, including accusations on their part that you were inappropriate or abusive somehow. Remember, they will lie, and also, since they lie, any agreement or resolution the two of you come up with will be broken by them anyway. Always try to have a witness in your dealing with a liar.
4)Document! Don't let a situation develop where it's your word against his or hers. Liars can be very smooth and practised in presenting a distorted reallity to your organziational superiors.
5)Let your integrity shine! Don't stoop to the liars level. Show your integrity consistently in such a way that if it ever comes down to your boss or others having to believe you or the liar it will be no contest.